async-group

Allows the execution of asynchronous tasks in a throttled manner. This is useful when executing promises which could have unwanted external effects, such as HTTP requests.

Usage

// The requests will be executed atmost 3 in parallel.
$q = new AsyncGroup(3)
$q.run(() => http.get("http://example.com"))
$q.run(() => http.get("http://example.com"))
$q.run(() => http.get("http://example.com"))
$q.run(() => http.get("http://example.com"))
$q.run(() => http.get("http://example.com"))

Description

class AsyncGroup creates a new group of async executions. The group is built with a maximum on maxConcurrent async executions.

var maxConcurrent = 10 // this is the default
$q = new AsyncGroup(maxConcurrent)

AsyncGroup.run(promiseFn) adds a promise to the async group. This promise will be started (by calling promiseFn) when a free slot is available. promiseFn must return a promise.

The return value is a Promise which will complete when the original promise will complete.

var myPromiseFn = function() {
  return http.get("http://example.com")
}
var myDelayedPromise = $q.run(myPromiseFn)
myDelayedPromise.then(function() {
  console.log('its done!')
})